/*
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 * and open the template in the editor.
 */

package com.totsp.gwittir.serial.json.client;

import com.google.gwt.core.client.JavaScriptObject;
import com.totsp.gwittir.serial.client.Codec;
import com.totsp.gwittir.serial.client.SerializationException;

/**
 *
 * @author rcooper
 */
public class JSONOverlayCodec<T extends JavaScriptObject> implements Codec<T> {

    public JSONOverlayCodec(){
        this.setup();
    }

    public String getMimeType() {
        return JSONCodec.MIME_TYPE;
    }

    public T deserialize(String data) throws SerializationException {
        return deserNative(data);
    }

    public String serialize(T object) throws SerializationException {
        return serNative(object);
    }

    private native T deserNative(String data) /*-{
          return JSON.parse(data);
     }-*/;

    private native String serNative(T object)/*-{
        return JSON.stringify(object);
    }-*/;

    private native void setup() /*-{
    if (!this.JSON) {
        this.JSON = {};
    }

    (function () {

        function f(n) {
            // Format integers to have at least two digits.
            return n < 10 ? '0' + n : n;
        }

        if (typeof Date.prototype.toJSON !== 'function') {

            Date.prototype.toJSON = function (key) {

                return isFinite(this.valueOf()) ?
                       this.getUTCFullYear()   + '-' +
                     f(this.getUTCMonth() + 1) + '-' +
                     f(this.getUTCDate())      + 'T' +
                     f(this.getUTCHours())     + ':' +
                     f(this.getUTCMinutes())   + ':' +
                     f(this.getUTCSeconds())   + 'Z' : null;
            };

            String.prototype.toJSON =
            Number.prototype.toJSON =
            Boolean.prototype.toJSON = function (key) {
                return this.valueOf();
            };
        }

        var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
            escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
            gap,
            indent,
            meta = {    // table of character substitutions
                '\b': '\\b',
                '\t': '\\t',
                '\n': '\\n',
                '\f': '\\f',
                '\r': '\\r',
                '"' : '\\"',
                '\\': '\\\\'
            },
            rep;


        function quote(string) {

        // If the string contains no control characters, no quote characters, and no
        // backslash characters, then we can safely slap some quotes around it.
        // Otherwise we must also replace the offending characters with safe escape
        // sequences.

                escapable.lastIndex = 0;
                return escapable.test(string) ?
                    '"' + string.replace(escapable, function (a) {
                        var c = meta[a];
                        return typeof c === 'string' ? c :
                            '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                    }) + '"' :
                    '"' + string + '"';
            }


            function str(key, holder) {

        // Produce a string from holder[key].

                var i,          // The loop counter.
                    k,          // The member key.
                    v,          // The member value.
                    length,
                    mind = gap,
                    partial,
                    value = holder[key];

        // If the value has a toJSON method, call it to obtain a replacement value.

                if (value && typeof value === 'object' &&
                        typeof value.toJSON === 'function') {
                    value = value.toJSON(key);
                }

        // If we were called with a replacer function, then call the replacer to
        // obtain a replacement value.

                if (typeof rep === 'function') {
                    value = rep.call(holder, key, value);
                }

        // What happens next depends on the value's type.

                switch (typeof value) {
                case 'string':
                    return quote(value);

                case 'number':

        // JSON numbers must be finite. Encode non-finite numbers as null.

                    return isFinite(value) ? String(value) : 'null';

                case 'boolean':
                case 'null':

        // If the value is a boolean or null, convert it to a string. Note:
        // typeof null does not produce 'null'. The case is included here in
        // the remote chance that this gets fixed someday.

                    return String(value);

        // If the type is 'object', we might be dealing with an object or an array or
        // null.

                case 'object':

        // Due to a specification blunder in ECMAScript, typeof null is 'object',
        // so watch out for that case.

                    if (!value) {
                        return 'null';
                    }

        // Make an array to hold the partial results of stringifying this object value.

                    gap += indent;
                    partial = [];

        // Is the value an array?

                    if (Object.prototype.toString.apply(value) === '[object Array]') {

        // The value is an array. Stringify every element. Use null as a placeholder
        // for non-JSON values.

                        length = value.length;
                        for (i = 0; i < length; i += 1) {
                            partial[i] = str(i, value) || 'null';
                        }

        // Join all of the elements together, separated with commas, and wrap them in
        // brackets.

                        v = partial.length === 0 ? '[]' :
                            gap ? '[\n' + gap +
                                    partial.join(',\n' + gap) + '\n' +
                                        mind + ']' :
                                  '[' + partial.join(',') + ']';
                        gap = mind;
                        return v;
                    }

        // If the replacer is an array, use it to select the members to be stringified.

                    if (rep && typeof rep === 'object') {
                        length = rep.length;
                        for (i = 0; i < length; i += 1) {
                            k = rep[i];
                            if (typeof k === 'string') {
                                v = str(k, value);
                                if (v) {
                                    partial.push(quote(k) + (gap ? ': ' : ':') + v);
                                }
                            }
                        }
                    } else {

        // Otherwise, iterate through all of the keys in the object.

                        for (k in value) {
                            if (Object.hasOwnProperty.call(value, k)) {
                                v = str(k, value);
                                if (v) {
                                    partial.push(quote(k) + (gap ? ': ' : ':') + v);
                                }
                            }
                        }
                    }

        // Join all of the member texts together, separated with commas,
        // and wrap them in braces.

                    v = partial.length === 0 ? '{}' :
                        gap ? '{\n' + gap + partial.join(',\n' + gap) + '\n' +
                                mind + '}' : '{' + partial.join(',') + '}';
                    gap = mind;
                    return v;
                }
            }

        // If the JSON object does not yet have a stringify method, give it one.

            if (typeof JSON.stringify !== 'function') {
                JSON.stringify = function (value, replacer, space) {

        // The stringify method takes a value and an optional replacer, and an optional
        // space parameter, and returns a JSON text. The replacer can be a function
        // that can replace values, or an array of strings that will select the keys.
        // A default replacer method can be provided. Use of the space parameter can
        // produce text that is more easily readable.

                    var i;
                    gap = '';
                    indent = '';

        // If the space parameter is a number, make an indent string containing that
        // many spaces.

                    if (typeof space === 'number') {
                        for (i = 0; i < space; i += 1) {
                            indent += ' ';
                        }

        // If the space parameter is a string, it will be used as the indent string.

                    } else if (typeof space === 'string') {
                        indent = space;
                    }

        // If there is a replacer, it must be a function or an array.
        // Otherwise, throw an error.

                    rep = replacer;
                    if (replacer && typeof replacer !== 'function' &&
                            (typeof replacer !== 'object' ||
                             typeof replacer.length !== 'number')) {
                        throw new Error('JSON.stringify');
                    }

        // Make a fake root object containing our value under the key of ''.
        // Return the result of stringifying the value.

                    return str('', {'': value});
                };
            }


        // If the JSON object does not yet have a parse method, give it one.

            if (typeof JSON.parse !== 'function') {
                JSON.parse = function (text, reviver) {

        // The parse method takes a text and an optional reviver function, and returns
        // a JavaScript value if the text is a valid JSON text.

                    var j;

                    function walk(holder, key) {

        // The walk method is used to recursively walk the resulting structure so
        // that modifications can be made.

                        var k, v, value = holder[key];
                        if (value && typeof value === 'object') {
                            for (k in value) {
                                if (Object.hasOwnProperty.call(value, k)) {
                                    v = walk(value, k);
                                    if (v !== undefined) {
                                        value[k] = v;
                                    } else {
                                        delete value[k];
                                    }
                                }
                            }
                        }
                        return reviver.call(holder, key, value);
                    }


        // Parsing happens in four stages. In the first stage, we replace certain
        // Unicode characters with escape sequences. JavaScript handles many characters
        // incorrectly, either silently deleting them, or treating them as line endings.

                    cx.lastIndex = 0;
                    if (cx.test(text)) {
                        text = text.replace(cx, function (a) {
                            return '\\u' +
                                ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                        });
                    }

        // In the second stage, we run the text against regular expressions that look
        // for non-JSON patterns. We are especially concerned with '()' and 'new'
        // because they can cause invocation, and '=' because it can cause mutation.
        // But just to be safe, we want to reject all unexpected forms.

        // We split the second stage into 4 regexp operations in order to work around
        // crippling inefficiencies in IE's and Safari's regexp engines. First we
        // replace the JSON backslash pairs with '@' (a non-JSON character). Second, we
        // replace all simple value tokens with ']' characters. Third, we delete all
        // open brackets that follow a colon or comma or that begin the text. Finally,
        // we look to see that the remaining characters are only whitespace or ']' or
        // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.

                    if (/^[\],:{}\s]*$/.
        test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@').
        replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
        replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {

        // In the third stage we use the eval function to compile the text into a
        // JavaScript structure. The '{' operator is subject to a syntactic ambiguity
        // in JavaScript: it can begin a block or an object literal. We wrap the text
        // in parens to eliminate the ambiguity.

                        j = eval('(' + text + ')');

        // In the optional fourth stage, we recursively walk the new structure, passing
        // each name/value pair to a reviver function for possible transformation.

                        return typeof reviver === 'function' ?
                            walk({'': j}, '') : j;
                    }

        // If the text is not JSON parseable, then a SyntaxError is thrown.

                    throw new SyntaxError('JSON.parse');
                };
            }
        }());

     }-*/;
}
